Measured Wind Waves in Lake Pontchartrain

During Hurricane Katrina

AU: * McGehee, D D   Email:
AF: Emerald Ocean Engineering LLC, 107 Ariola Drive, Pensacola Beach, FL 32561 US
AU: Winer, H    Email: Harley.S.Winer@mvn02.usace.army.mil
AF: US Army Corps of Engineers New Orleans District, 7400 Leake Ave., New Orleans, LA 70118-3651 US
AU: Earle, M    Email: MEarle@PLANSYS.COM
AF: Neptune Sciences Division, Planning Systems Inc., 40201 Hiway 190 East, Slidell, LA 70461 US
AU: Smith, R    Email: RSmith@PLANSYS.COM
AF: Neptune Sciences Division, Planning Systems Inc., 40201 Hiway 190 East, Slidell, LA 70461 US
AU: Mesa, C     Email: Chuck.Mesa@spl01.usace.army.mil
AF: US Amy Corps of Engineers, Los Angeles District, P.O. Box 532711, Los Angeles, CA 90053-2325 US
AU: Pollock, C     Email: Cheryl.E.Pollock@erdc.usace.army.mil
AF: US Army Engineer research and Development Center, 3909 Halls Ferry Road, Vicksburg, MS 39180 US
AU: Hughes, B     Email: WHughes@PLANSYS.COM

AF: Neptune Sciences Division, Planning Systems Inc., 40201 Hiway 190 East, Slidell, LA 70461 US

ABSTRACT

A program for capturing episodic wave data in Lake Pontchartrain, LA using miniature rapidly-deployable wave buoys was implemented by the US Army Engineer District New Orleans. The data were intended for calibration and validation of numerical wave models used to investigate the risk of catastrophic flooding of New Orleans due to overtopping of the levees on the south shore of the lake. Several deployments during moderate storm events over the last three years demonstrated the viability of the approach, which relied on internal storage of the data and post-event recovery of the gages. Two days before landfall of Hurricane Katrina, three of the miniature buoys were deployed about mile offshore, just north of the 17th Street Canal. Winds were from the northern quadrant when Hurricane Katrina made landfall east of New Orleans, placing the levees, and the gages, at the locus of maximum fetch during the highest wind speeds. By the next day it was evident that the gages had encountered the event that was only supposed to be simulated. Capturing the data, however, was dependent upon recovering the buoys as soon as possible from a post-storm disaster scene that few had envisioned. This paper describes the extreme episodic data capture strategy, the gages, the sampling scheme, and the deployment and recovery methodology. One-dimensional energy spectra and non-directional wave parameters from two adjacent gages are compared and the quality control process is described. The final quality-assured data set of the entire storm event, from two days before landfall through 6 days afterward is presented. Lessons learned to improve efficiency and reliability of the system are discussed.